The Pt/MWCNT and Pt/C catalysts were synthesized using the carbonyl chemical route. The catalysts were physically and electrochemically characterized. An enhanced stability under potential cycling is obtained with Pt/MWCNT as compared to that of Pt/C. The evaluation of the electrochemical stability in a microfluidic fuel cell system was in good agreement with the results obtained in half-cell tests. Increasing the applied current from 10 to 40 mA, the Pt/MWCNT cathode potential in the fuel cell system depolarized 67% less than Pt/C. The performance of the fuel cell with Pt/MWCNT cathode was 2 times higher compared to Pt/C, under a constant current of 40 mA for 1000 s. The results from half-cell and fuel cell measurements showed that Pt/MWCNT is a more suitable cathode for microfluidic fuel cell than Pt/C due to the properties of the carbonaceous substrate. The Pt/MWCNT cathode was subsequently used in a formic acid microfluidic fuel cell to study several system parameters including formic acid concentration, cell orientation and bubble effect. (C) 2013 The Electrochemical Society. All rights reserved.